There was suppose to have been a testimonial of Charles Darwin disclaiming the "scientific proof" of his theory of evolution. Many have claimed that Darwin recanted late in life, on his death bed.
The story of Darwin's rebuttal did not start until about one generation later. His former nurse, Lady Hope, was able to join the lecture circuit with this claim, but without tangible evidence either way. Whether Darwin ended up believing in the theory of evolution or not, the damage has been done in his name. And ... if he did recant, on his death bed, they say, then he did not actually make any efforts to make his confession public.
The book: "In the Minds of Men" discusses this in Chapter 5 (Look for "Lady Hope.")
Karl Marx was a contemporary of Charles Darwin. Darwin's work was foundational for Marxism, as it claimed to have provided a means for explaining human existence without needing the Bible and its Creation. Marx read On the Origin of the Species twice in one year, shortly after its publication. Karl Marx had become an avowed atheist and Darwin's theory aided in the implementation of Marxism a couple of generations later with its (belief in "no rules" as a "liberator") mass murder by the millions. (No dusty old religious books to tell them that murder was wrong or other inhibitors!) An atheistic dictator was not bound by any rules regarding the treatment of his own people.
Lady Hope (was that her real name?) had motive to potentially invent
the story. It made her very popular among believers, and thus provided
an income for later in her life. And recall that the story did not
start to be spread until a couple of decades after his death.